class ModifyCommentDate < ActiveRecord::Migration
  def self.up
    rename_column :comments, :post_date, :create_at
    add_column :comments, :update_at, :datetime
    add_column :comments, :published_at, :datetime
  end

  def self.down
    rename_column :comments, :create_at, :post_date
    remove_column :comments, :update_at
    remove_column :comments, :published_at
  end
end
